diamond geezer

Tuesday, September 24, 2013

If you live in North London, you probably have a direct connection to Beckton Sewage Treatment Works. A series of interconnectingsewers runs parallel to the Thames, constructed in the 1860s by the great Joseph Bazalgette to divert the capital's effluent far downstream. His forward-thinking plans helped to ease chronic pollution and ill-health in the centre of town, and his fine Victorian craftsmanship is still delivering its cargo to Beckton 150 years later. Here Bazalgette's Northern Outfall Sewer fed waste into giant storage tanks, then flushed it out into the Thames with the tide so it despoiled Erith and Tilbury instead. But what awaits at Beckton today is Europe's largest sewage works, a massive undertaking, which Thames Water were more than keen to show off at the weekend. What better way of spending two hours than a minibus tour of an essential, if rather smelly, public utility? [6 photos][aerial shot]

Beckton Sewage Treatment Works covers 250 acres, that's a lot of land, which thankfully was available here in abundance. Nobody lives nearby, there's only industry and river and a couple of shopping centres, one of which was built on the site of Europe's largest gasworks. If you're ever shopping at Gallions Reach take a look beyond the metal warehouses to the raised bank beyond - that's where the Northern Outfall Sewer arrives, and that's where our tour began. We met Derry, the man whose job it is to keep an eye on the larger detritus that Londoners flush down their drains. The coarsescreens remove everything larger than 5cm across, that's mostly rags and nappies, which we watched being removed by the automated machinery. If you're one of those people who chuck inappropriate stuff down the sink or toilet bowl, creating clothballs and fatbergs, a trip here might teach you better.

Further screens and channels remove grit and plastics, slowly thinning down the water to murk-with-floaty-bits. We got to see this less than pleasant liquid in a just-collected bottle when Alan gave us a run-through of the sedimentation process. He was great, as you'd expect from a long-term employee, dashing around from tank to tank to explain everything in twenty minutes flat. The aeration tanks are amazing, 14 lanes of bubbling sludge erupting like underground springs, only rather browner. They're powered by a series of blowers housed in stark concrete bunkers, like you'd imagine at a nuclear missile site. Opposite is an equally huge area of settlement tanks - those circular pools you often see at sewage works - here attracting the odd seagull in search of best-not-think-what. And then there are the final settlement pools and holding tanks, the latter in the process of being covered over to prevent escaping odour so we'll have been some of the last civilians to peer inside.

The resulting thick sludge used to be taken by tanker out into the North Sea and dumped, but environmental rules now prohibit this. Instead it ends up dried and baked and burnt in Beckton's very own Sludge Power Generator. This is a modern shiny building that incinerates 'cake', and helps to keep the site at least part-sustained with electricity. Further self-generation comes from the construction of a new wind turbine, very recently erected and fitted out. This stands beside a brand new extension to the sewage works, designed to increase treatment capacity by 60%, which if all goes to plan should be part-switched-on for the first time today.

One of the reasons this additional capacity is required is the construction of the Lee Tunnel. Thames Water are building this underground link to prevent storm discharge into the river at Abbey Mills, which is my local bit of the Lea so I'm well pleased. The Lee Tunnel will follow the Greenway from West Ham to Beckton, but at considerable depth because it's easier to dig through chalk not clay. We were taken to see the Beckton end, or at least the top of the overflow shaft, where cranes were delivering panels to be sunk 75m down to form the tunnel walls. This four mile storage tunnel is a massive undertaking, and interestingly almost completely uncontroversial unlike its big brother project, the Tideway Tunnel. Thames Water want to drive that beneath the Thames from Hammersmith to the Lea, at a cost of billions and with unwanted disruption to riverside amenities. They claim the Tideway Tunnel is essential, indeed they gave us all a glossy 24 page booklet (and a promotional pack of mints) to put their argument most strongly. Bazalgette would probably agree.

I do love Open House for the opportunity to get inside places you'd never normally get inside, and Beckton must be one of the biggest. It was truly fascinating to discover how London copes with its effluent issue, and to see just how many processes are required to clean that liquid from muck to clear. And the smell wasn't as strong as you'd expect, thankfully, although I might think twice about buying a flat downwind in Thames View Barking, just in case.